1. Field of the Invention
This disclosure relates to a vacuum pump, and more particularly, to a rotation body cleaning unit and a vacuum pump having the same.
2. Description of the Related Art
A process chamber for manufacturing a semiconductor device or a flat panel display is used together with various chemicals, such as a process gas. Byproducts and surplus gas in a process chamber are transferred to a gas scrubber through an exhaust unit such as a vacuum pump. The gas scrubber is employed to exhaust the byproducts and the surplus gas after washing/separating them out.
The vacuum pump is provided with a stator and a rotor. An inlet and an outlet are arranged in the stator. The rotor is placed in a pump chamber inside the stator. The vacuum pump may be a roots type, a screw type, a claw type, etc. according to the shape of the rotor.
FIG. 1 is a partial perspective view of a conventional vacuum pump.
Referring to FIG. 1, the conventional vacuum pump includes a rotation shaft 11, a pair of lobes 12, and a first diaphragm 15. A second diaphragm (not shown) may be arranged to face the first diaphragm 15. A cylinder wall (not shown) may be arranged to surround a pump chamber 17 between the first diaphragm 15 and the second diaphragm. The cylinder wall is provided with an inlet and an outlet. The cylinder wall, the first diaphragm 15 and the second diaphragm constitute a stator.
The rotation shaft 11 passes through the first diaphragm 15 and the second diaphragm. The pair of lobes 12 is attached to the rotation shaft 11 and opposite to each other. The pair of lobes 12 and the rotation shaft 11 constitutes a rotor 13. That is, the rotor 13 is placed in the pump chamber 17. In the pump chamber 17, two rotors 13 are situated to be engaged with each other.
By rotating the rotors 13, a gas is drawn from the inlet into the pump chamber 17, and the drawn gas is exhausted through the outlet. In other words, the inlet is connected to the process chamber, and the outlet is connected to the gas scrubber. Byproducts are drawn from the process chamber to the pump chamber 17 through the inlet provided in the cylinder wall, and then exhausted from the pump chamber 17 toward the gas scrubber through the outlet.
Here, the byproducts are solidified as a byproduct lump 19 while passing through the pump chamber 17. Some byproduct lumps 19 may be adhered to the inside of the pump chamber 17.
When the byproduct lumps 19 are adhered to the lobes 12, the first diaphragm 15 or the second diaphragm, they interfere with the rotation of the rotors 13. As a result, the byproduct lumps 19 cause the pumps to be overhauled more frequently and to malfunction.
To solve the foregoing problems, a method of heating the stator has recently been proposed. However, this method not only requires the stator to be made of a material having high heat transfer efficiency, but also needs additional devices and energy to heat the stator.
Embodiments of the invention address these and other limitations in the prior art.